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MAGNETIC RESONANCE IMAGING > PRELIMS > Flashcards

PRELIMS Flashcards

1
Q

The medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body.

A

MRI

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2
Q

MRI scanners use strong ______ fields, magnetic field ________, and _______ waves to generate images of the organs in the body.

A
  1. strong magnetic field
  2. magnetic field gradients
  3. radiowaves
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3
Q

He is the inventor of the first magnetic resonance scanning machine celebrates his 85th birthday on March 16.

A

Dr. Raymond Damadian

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4
Q

He is a physician performed the first full-body scan of a human being in 1977.

A

Dr. Raymond Damadian

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5
Q

MR imaging was invented by _____ _ __________ mechanism to encode spatial information into who developed NMR signal using magnetic field gradients in September 1971; he published the theory behind it in March 1973.

A

Paul C. Lauterbur

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6
Q

Damadian built the first whole-body MRI scanner in 1977, which he called the __________ (impossible).

A

Indomitable

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7
Q

_________ was able to image a student’s finger in 15-23 minutes in 1974.

A

Mansfield

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8
Q

_______________ is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials.

A

magnetic field

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9
Q

___________ is a material or object that produces a magnetic field.

A

magnet

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10
Q

it is the small, dense region consisting of protons and neutrons at the center of an atom

A

atomic nucleus

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11
Q

In 1911, he discovered the atomic nucleus based on the 1990 Geiger-Marsden Gold Foil experiment.

A

Ernest Rutherford

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12
Q

________ is a quantum-mechanical property, akin to the angular momentum of a classical sphere rotating on its axis, except it comes in discrete units of integer or half-integer multiples of ħ.

A

proton spin

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13
Q

_______________ is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated medium frequency alternating current.

A

radiofrequency

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14
Q

Radiofrequency ablation also called ___________.

A

fulguration

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15
Q

These are materials where the magnetic field is generated by the internal structure of the material itself.

A

permanent magnet

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16
Q

the uniform magnetic field is found inside the coil, especially in the center

these magnets are relatively inexpensive to make but require a large constant flow of current while magnetized and imaging

A

resistive magnet

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17
Q

a superconducting magnet is an elecromagnet made from coils of superconducting wire

most MRI systems use this magnet

A

superconductive magnet

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18
Q

is the time constant which determines the rate at which excited protons reach equilibrium or go out of phase with each other

it is a measure of the time taken for spinning protons to the coherence among the nuclei spinning perpendicular to the field

A

T2 or Transverse Relaxation Time

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19
Q

is the concentration of signal bearing spins

A

spin density

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20
Q

TR is the amount of time between successive pulse sequences applied to the same slice

A

repetition time

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21
Q

TE is the time between the delivery of the rf pulse and the receipt of echo signal

A

time to echo

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22
Q

often denoted by the symbol gamma

it is the ratio of the magnetic momentum in a particle to its angular momentum

A

gyromagnetic ratio

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23
Q

is a measure of torque exerted on a magnetic system (bar magnet or dipole) when placed in a magnetic field and that for a magnet is the product of the distance between its poles and the strength of either pole

A

magnetic momentum

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24
Q

also known as spin, is the velocity of rotation of something around an axis

A

angular momentum

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25
Q

are the simple devices that exploit the conservation of angular momentum to stabilize, guide or measure rotational movemeng in many types of systems

A

gyroscopes

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26
Q

is a special case of forced vibrations

when the frequency of an extremely applied periodic force on a body is ewual to its natural frequency, the body rapidly begins to vibrate with an increased volume

A

resonance

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27
Q

are critical to nuclear excitation and signal reception in MRI

A

radiofrequency fields

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28
Q

these frequencies are in the RF range which are much lower than xrays and do not disrupt living tissue

A

larmour frequency

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29
Q

is the summation of all the magnetic moments of the individusl hydrogen nuclei

A

net magnetization

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30
Q

Felix ____ and Edward ______ first discovered the properties of magnetic resonance

A

Felix Bloch and Edward Purcell

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31
Q

Felix Bloch and Edward Purcell used this technique for analysis of complex molecular structures and dynamic chemical processes

A

MRI spectroscopy

32
Q

device for transmitting or receiving radiowave

A

antenna

33
Q

spurious finding in or distortion of image

A

artifacts

34
Q

reduction in energy or amount kf a beam of radiation when it passes through tissue or other substances

A

attenuation

35
Q

single or multiple loops of wire designed to produce a magnetic field from the current flowing through a wave

A

coil

36
Q

the fear of a having no escape and being in closed or small spaces of rooms

A

claustrophobia

37
Q

relating to extremely low temperature

A

cryogenic

38
Q

spontaneous random motion of molecules in a medium

A

diffusion

39
Q

fat tissue in the image is made to be of a lower, darker signal intensity

A

fat suppressed images

40
Q

signal emitted by tissue after RF excitation

A

free induction decay

41
Q

technique used in reducing motion artifacts

A

gating

42
Q

fast pulse sequence, often used with 3D imaging to generate T2 weighted images

A

gradient echo

43
Q

a change in the intensity of a magnetic field in space

mT/cm

A

gradient magnetic field

44
Q

standard pulse sequence available in modt MRI imagers

A

inverse recovery

45
Q

a force is created when the magnetic dipole is in a magnetic field

A

magnetic moment

46
Q

the largest dcale macroscopic magnetic moment resulting from many nuclear magnetic moment

A

magnetization

47
Q

magnetic moments of individual hydrogen nuclei aligned in the external magnetic field

A

net magnetization

48
Q

flow of blood through vessels of an organ or anatomic structure

A

perfusion

49
Q

the wobble of the rotational axis of a spinning body about a spinning body about a stationary axis

A

precision

50
Q

SI unit of magnetic field strength

1T = 10,000 G

A

tesla

51
Q

suppresses signal from cerebospinal fluid (CSF)

A

fluid attenuated inversion recovery (FLAIR)

52
Q

the primary visual factor, determined by RF signal strength

A

brightness

53
Q

brighter than its surroundings

A

hyperintense

54
Q

darker than its surroundings

A

hypointense

55
Q

determined by the size and depth of tissue voxel

determines the smallest tissye differences that can be an image, therefore image resolution

A

section thickness

56
Q

manipulation of extrinsic parameters controls the acquisition of various T1, T2 and PD measurements thus affectijg image quality

A

imaging parameters

57
Q

ability to distinguish one structure from another

determined by the homogeneity of Bo, steepness of gradient fields and scan time

A

spatial resolution

58
Q

spatial resolution of current MRI is . mm

A

0.1 mm

59
Q

noise produced by increase random molecular motion with increase in body temperature

A

thermal noise

60
Q

extraneous visual information

A

signal to noise ratio

61
Q

metal with a paramagnetic effect

A

gadolinium

62
Q

a new manganese based paramagnetic liver contrast agent

used in detection, characterizatjon, localization and evaluation of lesions in the liver

A

teslascan

63
Q

an iron oxide mixture and the only supramagnetic contrast agentd available

used to detect and diagnose liver lesions

A

feridex

64
Q

technique used to organize the signal, for improving image quality, to reduce motion artifacts from the beating heart

A

gating

65
Q

uncontrolled by the operator

A

intrinsic

66
Q

controlled by the operator

A

extrinsic

67
Q

angle of inclination from the longitudinal axis

A

flip angle

68
Q

artifact

increase of T2 time, bright signal in tendons

A

magic angle artifact

69
Q

artifact

loss of contrast between two adjacent tissues

A

partial volume artifact

70
Q

artifact

signal dropouts, bright spots and spatial distortion

A

metal artifact

71
Q

artifact

blurring and ghosting

A

motion artifact

72
Q

artifact

static on image

A

herringbone artifact

73
Q

artifact

image non uniform

A

RF overflow/data clipping artifact

74
Q

artifact

localized inhomogenous brightness

A

shady artifact

75
Q

artifact

staircase like nuance

A

stair case artifact

76
Q

artifact

image wrap around

A

aliasing artifact

77
Q

artifact

bands through image center

A

zipper artifact

MAGNETIC RESONANCE IMAGING (2 decks)

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